1. Field of the Invention
The invention relates to an interface device between a boot and a ski for modifying the natural pressure distribution of a ski on its gliding surface. The invention also relates to a ski equipped with the interface device.
2. Description of Background and Relevant Information
Skis that are used for alpine skiing are comprised of relatively long beams on which the boots of the skier are retained by front and rear binding elements. The boots and the binding elements are located approximately in the median zone of the ski. At rest, the skis themselves have a natural camber, by which the median zone is naturally raised with respect to the front end of the ski, or shovel, and the rear end of the ski, or tail. In addition, the skis have a flexibility that is due to their internal structure. During skiing, the ski is deformed in an elastic manner in response to the different forces to which it is subjected by the skier, but also by the ground on which it glides.
Interface devices exist that are interposed between the binding elements and the ski. Such interfaces are, for example, known according to International Patent Publication No. WO 83/03360, European Patent Publication No. 0,492,658, and European Patent Publication No. 0,409,749. These devices modify the flexibility of the beam of the ski, by stiffening it, or with a shock absorbing effect. However, these devices act in a passive manner, i.e., they only react to a predetermined bending of the ski.
Also known according to European Patent Publication No. 0,530,449, commonly owned with the instant application, is an interface device that modifies in a dynamic fashion the pressure distribution of the ski on the snow, as a function of the vertical forces that the skier exerts on his or her skis. This device includes a vertically movable sensor element that transmits to the base of the front binding element the vertical biases that it captures issuing from the boot. These biases are transmitted by means of a rocking device, and in one of the embodiments by means of a substantially horizontal linkage plate journalled on one side to the rocking device and on the other side to the base of the binding.
This device provides good results because of its dynamic nature, but it does not suit all situations or all types of skis. Namely, it lacks effectiveness in turn initiation.
According to French Patent Publication No. 2,654,636, a device is known that exerts an action on the camber of the ski by a traction effect on a linkage that connects the front and rear binding elements. This device has, in addition, a means to select the magnitude according to which it acts on the camber of the ski. Its action is limited, however, to a passive modification of the camber of the ski.